When you say proximity, switches are you referring to the Hall effect switches in the motor? or are these regular proximities used for limits or other?
If these ARE regular proximity switches it is rare and also bad practice to use these in encoder 5v supply, so I would tend to use the existing 5v for these, usually proximity switches are 24v, at least.
If the Vipers have a 5v output and it will supply the encoder current, then it should be no problem.
I would use the drive supply over a separate one, unless the forsaid current demand is a problem.
You need to know if the proximity's are sink or source output and the nature of the BOB input.
Al.
CNC, Mechatronics Integration and Custom Machine Design
“Logic will get you from A to B. Imagination will take you everywhere.”
Albert E.